Lesson 19.2 - Use a calculated value for a property

Player.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Engine
{
    public class Player : LivingCreature
    {
        public int Gold { get; set; }
        public int ExperiencePoints { get; set; }
        public int Level 
        {
            get { return ((ExperiencePoints / 100) + 1); }
        }
        public Location CurrentLocation { get; set; }
        public List<InventoryItem> Inventory { get; set; }
        public List<PlayerQuest> Quests { get; set; }

        public Player(int currentHitPoints, int maximumHitPoints, int gold, int experiencePoints) : base(currentHitPoints, maximumHitPoints)
        {
            Gold = gold;
            ExperiencePoints = experiencePoints;

            Inventory = new List<InventoryItem>();
            Quests = new List<PlayerQuest>();
        }

        public bool HasRequiredItemToEnterThisLocation(Location location)
        {
            if(location.ItemRequiredToEnter == null)
            {
                // There is no required item for this location, so return "true"
                return true;
            }

            // See if the player has the required item in their inventory
            foreach(InventoryItem ii in Inventory)
            {
                if(ii.Details.ID == location.ItemRequiredToEnter.ID)
                {
                    // We found the required item, so return "true"
                    return true;
                }
            }

            // We didn't find the required item in their inventory, so return "false"
            return false;
        }

        public bool HasThisQuest(Quest quest)
        {
            foreach(PlayerQuest playerQuest in Quests)
            {
                if(playerQuest.Details.ID == quest.ID)
                {
                    return true;
                }
            }

            return false;
        }

        public bool CompletedThisQuest(Quest quest)
        {
            foreach(PlayerQuest playerQuest in Quests)
            {
                if(playerQuest.Details.ID == quest.ID)
                {
                    return playerQuest.IsCompleted;
                }
            }

            return false;
        }

        public bool HasAllQuestCompletionItems(Quest quest)
        {
            // See if the player has all the items needed to complete the quest here
            foreach(QuestCompletionItem qci in quest.QuestCompletionItems)
            {
                bool foundItemInPlayersInventory = false;

                // Check each item in the player's inventory, to see if they have it, and enough of it
                foreach(InventoryItem ii in Inventory)
                {
                    if(ii.Details.ID == qci.Details.ID) // The player has the item in their inventory
                    {
                        foundItemInPlayersInventory = true;

                        if(ii.Quantity < qci.Quantity) // The player does not have enough of this item to complete the quest
                        {
                            return false;
                        }
                    }
                }

                // The player does not have any of this quest completion item in their inventory
                if(!foundItemInPlayersInventory)
                {
                    return false;
                }
            }

            // If we got here, then the player must have all the required items, and enough of them, to complete the quest.
            return true;
        }

        public void RemoveQuestCompletionItems(Quest quest)
        {
            foreach(QuestCompletionItem qci in quest.QuestCompletionItems)
            {
                foreach(InventoryItem ii in Inventory)
                {
                    if(ii.Details.ID == qci.Details.ID)
                    {
                        // Subtract the quantity from the player's inventory that was needed to complete the quest
                        ii.Quantity -= qci.Quantity;
                        break;
                    }
                }
            }
        }

        public void AddItemToInventory(Item itemToAdd)
        {
            foreach(InventoryItem ii in Inventory)
            {
                if(ii.Details.ID == itemToAdd.ID)
                {
                    // They have the item in their inventory, so increase the quantity by one
                    ii.Quantity++;

                    return; // We added the item, and are done, so get out of this function
                }
            }

            // They didn't have the item, so add it to their inventory, with a quantity of 1
            Inventory.Add(new InventoryItem(itemToAdd, 1));
        }

        public void MarkQuestCompleted(Quest quest)
        {
            // Find the quest in the player's quest list
            foreach(PlayerQuest pq in Quests)
            {
                if(pq.Details.ID == quest.ID)
                {
                    // Mark it as completed
                    pq.IsCompleted = true;

                    return; // We found the quest, and marked it complete, so get out of this function
                }
            }
        }
    }
}

SuperAdventure.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

using Engine;

namespace SuperAdventure
{
    public partial class SuperAdventure : Form
    {
        private Player _player;
        private Monster _currentMonster;

        public SuperAdventure()
        {
            InitializeComponent();

            _player = new Player(10, 10, 20, 0);
            MoveTo(World.LocationByID(World.LOCATION_ID_HOME));
            _player.Inventory.Add(new InventoryItem(World.ItemByID(World.ITEM_ID_RUSTY_SWORD), 1));

            UpdatePlayerStats();
        }

        private void btnNorth_Click(object sender, EventArgs e)
        {
            MoveTo(_player.CurrentLocation.LocationToNorth);
        }

        private void btnEast_Click(object sender, EventArgs e)
        {
            MoveTo(_player.CurrentLocation.LocationToEast);
        }

        private void btnSouth_Click(object sender, EventArgs e)
        {
            MoveTo(_player.CurrentLocation.LocationToSouth);
        }

        private void btnWest_Click(object sender, EventArgs e)
        {
            MoveTo(_player.CurrentLocation.LocationToWest);
        }

        private void MoveTo(Location newLocation)
        {
            //Does the location have any required items
            if(!_player.HasRequiredItemToEnterThisLocation(newLocation))
            {
                rtbMessages.Text += "You must have a " + newLocation.ItemRequiredToEnter.Name + " to enter this location." + Environment.NewLine;
                return;
            }

            // Update the player's current location
            _player.CurrentLocation = newLocation;

            // Show/hide available movement buttons
            btnNorth.Visible = (newLocation.LocationToNorth != null);
            btnEast.Visible = (newLocation.LocationToEast != null);
            btnSouth.Visible = (newLocation.LocationToSouth != null);
            btnWest.Visible = (newLocation.LocationToWest != null);

            // Display current location name and description
            rtbLocation.Text = newLocation.Name + Environment.NewLine;
            rtbLocation.Text += newLocation.Description + Environment.NewLine;

            // Completely heal the player
            _player.CurrentHitPoints = _player.MaximumHitPoints;

            // Update Hit Points in UI
            lblHitPoints.Text = _player.CurrentHitPoints.ToString();

            // Does the location have a quest?
            if(newLocation.QuestAvailableHere != null)
            {
                // See if the player already has the quest, and if they've completed it
                bool playerAlreadyHasQuest = _player.HasThisQuest(newLocation.QuestAvailableHere);
                bool playerAlreadyCompletedQuest = _player.CompletedThisQuest(newLocation.QuestAvailableHere);

                // See if the player already has the quest
                if(playerAlreadyHasQuest)
                {
                    // If the player has not completed the quest yet
                    if(!playerAlreadyCompletedQuest)
                    {
                        // See if the player has all the items needed to complete the quest
                        bool playerHasAllItemsToCompleteQuest = _player.HasAllQuestCompletionItems(newLocation.QuestAvailableHere);

                        // The player has all items required to complete the quest
                        if(playerHasAllItemsToCompleteQuest)
                        {
                            // Display message
                            rtbMessages.Text += Environment.NewLine;
                            rtbMessages.Text += "You complete the '" + newLocation.QuestAvailableHere.Name + "' quest." + Environment.NewLine;

                            // Remove quest items from inventory
                            _player.RemoveQuestCompletionItems(newLocation.QuestAvailableHere);

                            // Give quest rewards
                            rtbMessages.Text += "You receive: " + Environment.NewLine;
                            rtbMessages.Text += newLocation.QuestAvailableHere.RewardExperiencePoints.ToString() + " experience points" + Environment.NewLine;
                            rtbMessages.Text += newLocation.QuestAvailableHere.RewardGold.ToString() + " gold" + Environment.NewLine;
                            rtbMessages.Text += newLocation.QuestAvailableHere.RewardItem.Name + Environment.NewLine;
                            rtbMessages.Text += Environment.NewLine;

                            _player.ExperiencePoints += newLocation.QuestAvailableHere.RewardExperiencePoints;
                            _player.Gold += newLocation.QuestAvailableHere.RewardGold;

                            // Add the reward item to the player's inventory
                            _player.AddItemToInventory(newLocation.QuestAvailableHere.RewardItem);

                            // Mark the quest as completed
                            _player.MarkQuestCompleted(newLocation.QuestAvailableHere);
                        }
                    }
                }
                else
                {
                    // The player does not already have the quest

                    // Display the messages
                    rtbMessages.Text += "You receive the " + newLocation.QuestAvailableHere.Name + " quest." + Environment.NewLine;
                    rtbMessages.Text += newLocation.QuestAvailableHere.Description + Environment.NewLine;
                    rtbMessages.Text += "To complete it, return with:" + Environment.NewLine;
                    foreach(QuestCompletionItem qci in newLocation.QuestAvailableHere.QuestCompletionItems)
                    {
                        if(qci.Quantity == 1)
                        {
                            rtbMessages.Text += qci.Quantity.ToString() + " " + qci.Details.Name + Environment.NewLine;
                        }
                        else
                        {
                            rtbMessages.Text += qci.Quantity.ToString() + " " + qci.Details.NamePlural + Environment.NewLine;
                        }
                    }
                    rtbMessages.Text += Environment.NewLine;

                    // Add the quest to the player's quest list
                    _player.Quests.Add(new PlayerQuest(newLocation.QuestAvailableHere));
                }
            }

            // Does the location have a monster?
            if(newLocation.MonsterLivingHere != null)
            {
                rtbMessages.Text += "You see a " + newLocation.MonsterLivingHere.Name + Environment.NewLine;

                // Make a new monster, using the values from the standard monster in the World.Monster list
                Monster standardMonster = World.MonsterByID(newLocation.MonsterLivingHere.ID);

                _currentMonster = new Monster(standardMonster.ID, standardMonster.Name, standardMonster.MaximumDamage,
                    standardMonster.RewardExperiencePoints, standardMonster.RewardGold, standardMonster.CurrentHitPoints, standardMonster.MaximumHitPoints);

                foreach(LootItem lootItem in standardMonster.LootTable)
                {
                    _currentMonster.LootTable.Add(lootItem);
                }

                cboWeapons.Visible = true;
                cboPotions.Visible = true;
                btnUseWeapon.Visible = true;
                btnUsePotion.Visible = true;
            }
            else
            {
                _currentMonster = null;

                cboWeapons.Visible = false;
                cboPotions.Visible = false;
                btnUseWeapon.Visible = false;
                btnUsePotion.Visible = false;
            }

            // Refresh player's stats
            UpdatePlayerStats();

            // Refresh player's inventory list
            UpdateInventoryListInUI();

            // Refresh player's quest list
            UpdateQuestListInUI();

            // Refresh player's weapons combobox
            UpdateWeaponListInUI();

            // Refresh player's potions combobox
            UpdatePotionListInUI();

            ScrollToBottomOfMessages();
        }

        private void UpdatePlayerStats()
        {
            // Refresh player information and inventory controls
            lblHitPoints.Text = _player.CurrentHitPoints.ToString();
            lblGold.Text = _player.Gold.ToString();
            lblExperience.Text = _player.ExperiencePoints.ToString();
            lblLevel.Text = _player.Level.ToString();
        }

        private void UpdateInventoryListInUI()
        {
            dgvInventory.RowHeadersVisible = false;

            dgvInventory.ColumnCount = 2;
            dgvInventory.Columns[0].Name = "Name";
            dgvInventory.Columns[0].Width = 197;
            dgvInventory.Columns[1].Name = "Quantity";

            dgvInventory.Rows.Clear();

            foreach(InventoryItem inventoryItem in _player.Inventory)
            {
                if(inventoryItem.Quantity > 0)
                {
                    dgvInventory.Rows.Add(new[] { inventoryItem.Details.Name, inventoryItem.Quantity.ToString() });
                }
            }
        }

        private void UpdateQuestListInUI()
        {
            dgvQuests.RowHeadersVisible = false;

            dgvQuests.ColumnCount = 2;
            dgvQuests.Columns[0].Name = "Name";
            dgvQuests.Columns[0].Width = 197;
            dgvQuests.Columns[1].Name = "Done?";

            dgvQuests.Rows.Clear();

            foreach(PlayerQuest playerQuest in _player.Quests)
            {
                dgvQuests.Rows.Add(new[] { playerQuest.Details.Name, playerQuest.IsCompleted.ToString() });
            }
        }

        private void UpdateWeaponListInUI()
        {
            List<Weapon> weapons = new List<Weapon>();

            foreach(InventoryItem inventoryItem in _player.Inventory)
            {
                if(inventoryItem.Details is Weapon)
                {
                    if(inventoryItem.Quantity > 0)
                    {
                        weapons.Add((Weapon)inventoryItem.Details);
                    }
                }
            }

            if(weapons.Count == 0)
            {
                // The player doesn't have any weapons, so hide the weapon combobox and "Use" button
                cboWeapons.Visible = false;
                btnUseWeapon.Visible = false;
            }
            else
            {
                cboWeapons.DataSource = weapons;
                cboWeapons.DisplayMember = "Name";
                cboWeapons.ValueMember = "ID";

                cboWeapons.SelectedIndex = 0;
            }
        }

        private void UpdatePotionListInUI()
        {
            List<HealingPotion> healingPotions = new List<HealingPotion>();

            foreach(InventoryItem inventoryItem in _player.Inventory)
            {
                if(inventoryItem.Details is HealingPotion)
                {
                    if(inventoryItem.Quantity > 0)
                    {
                        healingPotions.Add((HealingPotion)inventoryItem.Details);
                    }
                }
            }

            if(healingPotions.Count == 0)
            {
                // The player doesn't have any potions, so hide the potion combobox and "Use" button
                cboPotions.Visible = false;
                btnUsePotion.Visible = false;
            }
            else
            {
                cboPotions.DataSource = healingPotions;
                cboPotions.DisplayMember = "Name";
                cboPotions.ValueMember = "ID";

                cboPotions.SelectedIndex = 0;
            }
        }

        private void btnUseWeapon_Click(object sender, EventArgs e)
        {
            // Get the currently selected weapon from the cboWeapons ComboBox
            Weapon currentWeapon = (Weapon)cboWeapons.SelectedItem;

            // Determine the amount of damage to do to the monster
            int damageToMonster = RandomNumberGenerator.NumberBetween(currentWeapon.MinimumDamage, currentWeapon.MaximumDamage);

            // Apply the damage to the monster's CurrentHitPoints
            _currentMonster.CurrentHitPoints -= damageToMonster;

            // Display message
            rtbMessages.Text += "You hit the " + _currentMonster.Name + " for " + damageToMonster.ToString() + " points." + Environment.NewLine;

            // Check if the monster is dead
            if(_currentMonster.CurrentHitPoints <= 0)
            {
                // Monster is dead
                rtbMessages.Text += Environment.NewLine;
                rtbMessages.Text += "You defeated the " + _currentMonster.Name + Environment.NewLine;

                // Give player experience points for killing the monster
                _player.ExperiencePoints += _currentMonster.RewardExperiencePoints;
                rtbMessages.Text += "You receive " + _currentMonster.RewardExperiencePoints.ToString() + " experience points" + Environment.NewLine;

                // Give player gold for killing the monster 
                _player.Gold += _currentMonster.RewardGold;
                rtbMessages.Text += "You receive " + _currentMonster.RewardGold.ToString() + " gold" + Environment.NewLine;

                // Get random loot items from the monster
                List<InventoryItem> lootedItems = new List<InventoryItem>();

                // Add items to the lootedItems list, comparing a random number to the drop percentage
                foreach(LootItem lootItem in _currentMonster.LootTable)
                {
                    if(RandomNumberGenerator.NumberBetween(1, 100) <= lootItem.DropPercentage)
                    {
                        lootedItems.Add(new InventoryItem(lootItem.Details, 1));
                    }
                }

                // If no items were randomly selected, then add the default loot item(s).
                if(lootedItems.Count == 0)
                {
                    foreach(LootItem lootItem in _currentMonster.LootTable)
                    {
                        if(lootItem.IsDefaultItem)
                        {
                            lootedItems.Add(new InventoryItem(lootItem.Details, 1));
                        }
                    }
                }

                // Add the looted items to the player's inventory
                foreach(InventoryItem inventoryItem in lootedItems)
                {
                    _player.AddItemToInventory(inventoryItem.Details);

                    if(inventoryItem.Quantity == 1)
                    {
                        rtbMessages.Text += "You loot " + inventoryItem.Quantity.ToString() + " " + inventoryItem.Details.Name +Environment.NewLine;
                    }
                    else
                    {
                        rtbMessages.Text += "You loot " + inventoryItem.Quantity.ToString() + " " + inventoryItem.Details.NamePlural + Environment.NewLine;
                    }
                }

                UpdatePlayerStats();
                UpdateInventoryListInUI();
                UpdateWeaponListInUI();
                UpdatePotionListInUI();

                // Add a blank line to the messages box, just for appearance.
                rtbMessages.Text += Environment.NewLine;

                // Move player to current location (to heal player and create a new monster to fight)
                MoveTo(_player.CurrentLocation);
            }
            else
            {
                // Monster is still alive

                // Determine the amount of damage the monster does to the player
                int damageToPlayer = RandomNumberGenerator.NumberBetween(0, _currentMonster.MaximumDamage);

                // Display message
                rtbMessages.Text += "The " + _currentMonster.Name + " did " + damageToPlayer.ToString() + " points of damage." + Environment.NewLine;

                // Subtract damage from player
                _player.CurrentHitPoints -= damageToPlayer;

                // Refresh player data in UI
                lblHitPoints.Text = _player.CurrentHitPoints.ToString();

                if(_player.CurrentHitPoints <= 0)
                {
                    // Display message
                    rtbMessages.Text += "The " + _currentMonster.Name + " killed you." + Environment.NewLine;

                    // Move player to "Home"
                    MoveTo(World.LocationByID(World.LOCATION_ID_HOME));
                }
            }

            ScrollToBottomOfMessages();
        }

        private void btnUsePotion_Click(object sender, EventArgs e)
        {
            // Get the currently selected potion from the combobox
            HealingPotion potion = (HealingPotion)cboPotions.SelectedItem;

            // Add healing amount to the player's current hit points
            _player.CurrentHitPoints = (_player.CurrentHitPoints + potion.AmountToHeal);

            // CurrentHitPoints cannot exceed player's MaximumHitPoints
            if(_player.CurrentHitPoints > _player.MaximumHitPoints)
            {
                _player.CurrentHitPoints = _player.MaximumHitPoints;
            }

            // Remove the potion from the player's inventory
            foreach(InventoryItem ii in _player.Inventory)
            {
                if(ii.Details.ID == potion.ID)
                {
                    ii.Quantity--;
                    break;
                }
            }

            // Display message
            rtbMessages.Text += "You drink a " + potion.Name + Environment.NewLine;

            // Monster gets their turn to attack

            // Determine the amount of damage the monster does to the player
            int damageToPlayer = RandomNumberGenerator.NumberBetween(0, _currentMonster.MaximumDamage);

            // Display message
            rtbMessages.Text += "The " + _currentMonster.Name + " did " + damageToPlayer.ToString() + " points of damage." + Environment.NewLine;

            // Subtract damage from player
            _player.CurrentHitPoints -= damageToPlayer;

            if(_player.CurrentHitPoints <= 0)
            {
                // Display message
                rtbMessages.Text += "The " + _currentMonster.Name + " killed you." + Environment.NewLine;

                // Move player to "Home"
                MoveTo(World.LocationByID(World.LOCATION_ID_HOME));
            }

            // Refresh player data in UI
            lblHitPoints.Text = _player.CurrentHitPoints.ToString();
            UpdateInventoryListInUI();
            UpdatePotionListInUI();

            ScrollToBottomOfMessages();
        }

        private void ScrollToBottomOfMessages()
        {
            rtbMessages.SelectionStart = rtbMessages.Text.Length;
            rtbMessages.ScrollToCaret();
        }
    }
}